Yes, that's a different argument tho. Border run companies probably get stopped more often then others while going to the border. Since they don't want negative reviews, etc, they just don't take overstays people which make sense. But I thought Ron meant normal visa agent, not border run visa agent.
If by long you mean since Covid, fair enough, if you mean before that, I've clear overstay in Nong Khai and Mukdahan with no issue from 2013 to 2018 ish. I don't have exact dates, I don't remember, I'm on my 3nd passport. p.s: Agent do take people on overstay, they can sort you out of many situations including overstays. First, they get you out of the overstay, and then provide the visa or extension. It's costly tho. I know at least 2 agents that can help, one is in Pattaya.
Yes, you can go to immigration, pay the 7.5k baht fine plus 1.9k baht for the extension and get 30 days, but that 30 days is now 15 because you were already 15 days late for the extension. So you will get stamped until January 10 ish. No, you cannot get arrested at immigration office. Many people go there late, pay the overstay and get their 30 days minus the overstay days. Edit: You are on yearly extension, my bad, go there, pay the fine, show the money in bank and extend another year (no idea which yearly extension you are on).